December 10, 2025, Planning Board Special Meeting - WEHI Transcript

31 of 55 sheets Page 121 to 124 of 144 01/14/2026 10:36:25 AM 121 and there's blasting and construction, how, what is the1 magnitude or reach to other joints in that area? So if2 you had to blast some rock or to put in the emergency3 roadway with asphalt or blast or dig or cause vibration,4 how far could those vibrations occur and cause issues?5 Not just directly below Building D but a little on the6 outskirts, what's the likelihood of that?7 THE WITNESS: We recommended, I think, in8 the report that if blasting is done it should be9 controlled and there's a procedure where they, they can10 design the blasting, the way that the explosives, in11 order to limit it, in order to minimize the disturbance12 at a distance. So we recommended that they consider the13 distance to be, the distance to the top of the slope,14 which is only 10 or 15-feet from the line of the15 excavation. So that would, assuming that, that this is16 the type of control that is established, that, that17 blasting would be designed so that the ground motion is18 not severe.19 THE PUBLIC: Severe in terms of, you're20 saying 50-feet 100-feet, so when you're 200-feet away21 would you feel something move or if there was an issue22 going on already in the slope would that be affected?23 THE WITNESS: Well, they use a motion24 criterion. A velocity vibration inches per second. For25 122 instance, if you were blasting for a sewer in a1 residential street you would size it so that the, the2 velocity of the vibration, which they monitor with a3 device, is lower, is lower so that it would not create a4 disturbance.5 THE PUBLIC: So would you recommend to the6 board that a full blasting and vibration impact study be7 required to protect the homes in and around Howell Drive8 and beyond before construction or approval?9 THE PUBLIC: We recommended that a, that an10 earth work, an earth work control plan be submitted11 before construction is approved.12 THE PUBLIC: Is that an earth -- I'm sorry.13 Is an earth work plan different than a basting impact14 study?15 THE WITNESS: No, that would include that.16 THE PUBLIC: Okay. I'm sorry.17 THE WITNESS: Whatever excavation they would18 do they would have to explain, come up with a monitoring19 program to do that. We recommended that they install20 what are called, slope indicators, which measure the21 amount of ground movement and so we recommended they

explain, come up with a monitoring19 program to do that. We recommended that they install20 what are called, slope indicators, which measure the21 amount of ground movement and so we recommended they be22 installed prior to construction and monitored both23 during and after construction to confirm that slope24 movements are not occurring due to the construction.25 123 That was one of the requirements we recommended that the1 board establish.2 THE PUBLIC: So given, I believe that you3 acknowledged that this slope falls into a higher land4 slide prone class, is that correct? Than Langan5 assumed.6 THE WITNESS: No, that's what the -- there7 was a hazard area map, Langan did a subsurface8 investigation of the stability calculation that did not9 indicate that there is instability. So that's, and10 Princeton Hydro also did an analysis and their safety11 factors were pretty much very close.12 THE PUBLIC: You think, I mean I know you13 did some great comparisons and I do thank you for that14 in trying to help this board achieve, but don't you15 think that might have been a little bit better if you16 were just given the full scope to do your independent17 geotechnical verification with the whole works and not18 just numbers and really being out there and really19 digging your own bores where you want to and really20 trying to make heads or tails, because I feel like we21 are just crunching a lot of numbers from an ivory tower22 and wouldn't it be better if you were just given the23 option to do your full own independent report assessment24 and dig where you needed to, to find out what's going on25 124 here?1 THE WITNESS: Well, I am going to say both2 of the engineering firms who did the comments and did3 comments on the slope stability evaluation are4 representable and highly qualified engineering firms.5 THE PUBLIC: Agreed.6 THE WITNESS: I don't know that what we would7 do would add to it.8 THE PUBLIC: But we are still at a point9 where you designate this as a known hazard zone for10 construction?11 THE WITNESS: As a known hazard. No, I12 would not. There are, there have to be precautions13 during construction to not create a situation, but they14 don't appear to exist now based on the calculations that15 were done and the appearance of the site.16 THE PUBLIC: Okay. Thank you.17 CHAIRMAN BAGOFF: Thank you.18 THE PUBLIC: Jessica Pearson.19 Mr. Chairman, I have a

xist now based on the calculations that15 were done and the appearance of the site.16 THE PUBLIC: Okay. Thank you.17 CHAIRMAN BAGOFF: Thank you.18 THE PUBLIC: Jessica Pearson.19 Mr. Chairman, I have a question for the20 board, just because I don't understand the appearance of21 documents that I don't think were there today, this22 afternoon. Mr. Kleinberg e-mailed a site plan with23 markings and the disappearance of a CME letter on the24 sanitary sewer that was there this morning and now it's25